In order to improve the efficiency in gas chromatographic isotope separation technology, porous SiC supporting palladium-platinum (Pd-Pt) alloy as a column material was developed. It was confirmed that the utilization of the column material developed enabled higher recovery yield of 90 % and the higher purity of 97 % for deuterium isotopic separation comparing with the method using conventional column materials such as the mixture of Pd-Pt alloy filler under 100 mesh and Cu powder from 40 to 80 mesh.